


Rapture on the Lonely Shore

by tenrousei_kuroi



Category: Harry Potter - J. K. Rowling
Genre: (like really light don't worry), Breathplay, Brother/Brother Incest, First War with Voldemort, Frottage, Implied/Referenced Underage Sex, Light BDSM, M/M, Non-Canon Relationship, Not Canon Compliant, Psychological Trauma, Regulus Black Lives, Sibling Incest, Sirius Black is a Good Sibling
Language: English
Status: Completed
Published: 2020-12-18
Updated: 2020-12-18
Packaged: 2021-03-11 03:20:55
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 9,026
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28138335
Author URL: https://archiveofourown.org/users/tenrousei_kuroi/pseuds/tenrousei_kuroi
Summary: Orion sneaks Regulus into Azkaban to see his brother.
Relationships: Regulus Black/Sirius Black
Comments: 25
Kudos: 107





	Rapture on the Lonely Shore

**Author's Note:**

> Canon non-compliant. Regulus did not die in the cave, but Sirius is still in prison for the death of James and Lily. This is basically the premise of "Lucida" only starring Orion instead of Walburga...and with a lot more incest. 
> 
> Please head the rating and warnings!
> 
> Title credit to Lord Byron because of course. (“There is a pleasure in the pathless woods, there is a rapture on the lonely shore.”)

It was over. When Regulus heard the news that the Dark Lord was dead, he went weak in the knees. His hands trembled and he nearly collapsed in relief. Suddenly the heavy weight of the locket he’d hidden in his dresser drawer was nowhere near as maddening. The constant fear of being found out, of seeing himself and his whole family executed—gone.

He’d actually cried. Placed his hands over his face and sobbed quietly into his hands, all the tension falling from his body. The world was turning again.

Until it stopped.

His mother, who had been reading the breaking news post that had gone out in the Prophet that evening, suddenly went white in the face as the article began to get more detailed. The Dark Lord wasn’t just dead. He had died murdering Lily Evans and...James Potter.

At the behest of Sirius Black.

“What?” Regulus gasped and his parents both looked up at him. They hadn’t noticed his crying until that point.

“Get ahold of yourself, boy,” Orion snapped and Regulus hiccupped.

“No, I’m not—” Regulus started to explain but stopped. What sounded worse? _I’m crying over my blood traitor brother_ or _I’m crying because I betrayed the Dark Lord and now he can’t hurt me_?

“Enough, both of you,” Walburga said firmly. “This is...Orion, he’s...he’s been sentenced to _life._ ”

“In Azkaban,” Orion whispered, completing his wife’s thought. He took the paper from her and contemplated it for a moment. “It’s amazing he’s not going to be Kissed,” he murmured.

“To think Sirius would have betrayed James Potter to the Dark Lord. James _Potter_ of all people,” his mother bemoaned. “The two have been practically glued together since they met.”

Suddenly she turned sharply to Regulus. “How could you not have told us your brother had joined the cause?” she demanded.

“He—he didn’t,” Regulus stammered. “Mum, he wasn’t one of them—I mean, of us...”

“Are you sure?” she asked.

Regulus nodded. Orion strode around the table to grab his youngest son by the arm. Walburga looked at the two of them in concern but did not rise from her seat at the head of the table.

“How can you be sure you knew of every spy in the Dark Lord’s employ?”

“Father, I...” but Regulus had no real answer. Because he didn’t know everyone who worked for Lord Voldemort. He knew Sirius had not been a regular Death Eater; he would have recognized him in an instant. But that didn’t mean Sirius couldn’t have been a double agent. Regulus’s assertion really just came from his gut. He couldn’t believe that Sirius would have done such a thing, but that answer wasn’t going to satisfy his father.

His mother saved him from having to answer. “Sirius?” she scoffed. “A spy? Orion, the boy couldn’t keep his mouth shut for five minutes if you so much as disagreed with his favorite coffee roasts. Do you mean to tell me he could fake being on both sides of a _war_?”

Orion loosened his grip on Regulus. “You’re right,” he conceded. “More likely the bloody coward sold his little friends out in some sort of bargain to save his own hide.”

“You can’t let this happen.”

“What?” Orion looked at his wife in shock.

Now Walburga finally rose from the table. She was still taller than Regulus and met Orion nearly eye-to-eye. “My heir,” she said. “You will not leave him rotting in some jail cell like a common thief!”

“And since when has Sirius been any heir of yours?” Orion asked coolly.

A wicked smile spread over Walburga’s face. “Since he came crawling back to me, battered and torn from Azkaban with all his little Gryffindor friends dead in the ground.”

Regulus winced. “Am I not a suitable heir, mother?” he asked boldly.

Walburga ignored him and his father placed a warning hand on his shoulder.

“Sirius will not come back to us even if his friend is dead. He’s hopeless.”

Walburga pointed angrily at Regulus. “He’ll come back for _him_ ,” she hissed. Orion looked sharply to Regulus.

“Mother, I don’t think—”

“Silence!” Walburga insisted. “Do you think I didn’t notice how he fawned over you? How he coddled you like some sort of precious doll?”

Regulus’s heart began to beat frantically and his mouth went dry.

Walburga continued. “That ungrateful brat hadn’t been gone for a week before he was back at my door, begging, screaming, _threatening_ me to send you to him.”

“Sirius came back for me?” Regulus asked in disbelief. A slick heat was curling around his heart, followed immediately by a swell of anger that Sirius hadn’t tried harder. That he had let their mother scare him off.

“He is a selfish and ungrateful little mongrel...” she turned to Orion. “But he will come back if we give him the chance. And we can control him this time. He has nowhere else to turn,” Walburga insisted. “Orion, this is our chance to undo the shame he has caused us, and to ensure that any bastards he sires are true heirs. I’ll not have our family tree branch off into even more of an unrecognized mess if I can prevent it.”

“You’re not going to get any _heirs_ from Sirius,” Regulus blurted out without thinking. His father cuffed him on the head.

“Quiet,” he hissed. “You’re right,” he said to his wife. “This is our chance.”

Orion walked across the kitchen and seized his overcoat. Looking back, he said, “The death of Sirius’s friends will cast serious doubt around his character. We may be able to work that to our advantage. Let people believe whatever they want to believe, depending on the circumstance.”

“I will contact Crouch,” Walburga said.

“No,” Orion held up a hand. “Let us go and see the boy first. Make sure he’s...compliant. He’s not been in jail a day yet, Walburga, he may not be...agreeable.”

Walburga nodded. “Fine,” she said. “Go check him out. We can wait a short while if we need. Pierce and Dearborn are dead, after all, which means the Wizengamot leans definitely in our favor until they fill those vacancies.”

“We have time,” Orion insisted. He put on his gloves and pocketed his wand. “I will go immediately. I think it best if we send Regulus to him first. The two of them can get reacquainted.”

Walburga nodded.

“And then,” Orion continued. “If he remains too resistant, we might be able to offer a little incentive,” he murmured, gripping Regulus by his forearm and kneading painfully over his Dark Mark. Regulus looked at his mother with wide eyes.

Walburga was smiling. “Of course,” she agreed. “If you were to insinuate to that boy that we were considering turning Regulus in for his crimes, he would be ours in a heartbeat.”

“Mother!” Regulus said in horror. His heart began to race…

“Oh, calm yourself, Regulus,” Orion said shortly. He tugged his fingers through Regulus’s hair, pulling his head back and forcing him to look up at his father. “What your mother intends is a fallback ploy. We’ll not be really tossing you to the dementors, don’t be ridiculous.”

Regulus nodded, but remained nervous, even after his father released him. His parents continued to talk logistics.

“I think you should stay here and field any questions from family,” Orion said, reaching for the door.

Walburga nodded. “Regulus,” she said, looking towards Regulus, who still stood somewhat gormlessly in the middle of the kitchen floor. “Don’t keep your brother waiting.”

* * *

“You are to be talk to your brother and discern two things. One, did he do it? This will be useful information to know. And two, will he accept back his title and smooth things over with your mother? Regulus, are you paying attention to me?”

Regulus jolted from his reverie. The boat they were in swayed dangerously back and forth across the black waters. It had been a vicious argument getting the minister to allow Orion and Regulus passage to the prison at all, let alone after hours. Regulus hadn’t been allowed inside the room, but he had heard the shouting and suspected a good deal of gold had exchanged hands.

“Yes, father,” Regulus said, hugging his robes around him tighter. He’d not been given time to grab his cloak and he was freezing. Wet sea spray kept flying up into his face and the rocking of the boat was filling him with dread. The black water all around him was too similar to the water of that cave, and he half expected the cold, decaying arm of an inferi to reach up for him.

_Would his father even do anything if one did?_

“What if he doesn’t want to talk to me?” Regulus asked mildly. “Maybe you should see him.”

Orion snorted. “You are the only one he _will_ talk to. At least right now. Regulus, you will do this and you will do it well.”

The boat halted at the dock and Regulus stepped out on unsteady feet. Azkaban prison loomed large and foreboding in front of him. Already, Regulus could feel the pull of the dementors that lurked inside. Some of his worst fears and memories were starting to surface and he began to pant.

 _The cave, the cave, the cave…_ Regulus wasn’t sure what would happen if the dementors forced him to relieve his stint with the Horcrux. If he had a panic attack...if he spoke without thinking and his father found out what happened…

Orion pushed him forward and the two started up the craggy rock path, stumbling in the dark. Orion lit his wand and Regulus noticed the boat leave the dock to return to the mainland.

The iron doors of the prison opened with ease and Regulus shuddered. No locks were needed here.

When they stepped inside, they were greeted by a very damp and dark reception room. A few pathetic torches flickered on the walls, leading up to a desk that was glowing silver. Upon closer examination, Regulus saw the desk was surrounded by a long, snake-like patronus that was protecting the woman who sat behind it. Immediately, Regulus walked closer to the silver snake, drawn to its warmth and positivity.

“Orion Black?” the woman asked.

Orion nodded.

“I was informed about an hour ago that you would be coming.” She eyed Regulus critically. “I did not know you were going to be bringing company.”

“This is my son,” Orion explained.

“Yes, well...I’ll need you to fill out some extra forms,” she insisted in a bored tone.

“I can handle that while my son gets going,” Orion said.

The woman nodded, a little unsure of herself. She pulled out some forms and set them on the desk for Orion to parse through. “That’s the only door in or out,” she explained to Regulus, pointing to the heavy door behind her desk. “You’ll feel a slight tingling as you walk though it. That’s just the security scan. You’re allowed to cast a patronus to take with you, and your brother’s cell has been temporarily unlocked but the dementors will still be on the cell block, and they’ll know if anyone other than you leaves.”

“My son does not need to break his brother out of prison,” Orion said angrily. “The instant I want Sirius Black off of this island, I will have him, _legally._ ”

The woman nodded slowly. “All right...lad,” she turned back to Regulus. “I’d really recommend that patronus if you can cast it.”

“He can,” said Orion almost fiercely. “A raven. Regulus, cast your patronus.”

Regulus paused and looked nervously between his father and the woman. His patronus had never truly been a raven, although it had manifested as one briefly. Regulus’s patronus had changed in his sixth year, and its true form...his father had never seen.

“I’ll cast it when I get inside,” Regulus said in what he hoped was an off-hand voice. Then he left for the door before anyone could question him.

When the heavy door closed behind him, Regulus felt like he had been locked away. A part of him worried his father would leave him here, that maybe this had all been some cruel joke. Perhaps Sirius had already been freed and his father was just dropping him off, like a trade? Had his mother’s words been their true plan all along?

Regulus shook his head. He was being ridiculous, and the crushing panic he felt from the dementors wasn’t helping. The prison cell block was almost pitch black, but he could hear the dementors—as well as some of the more active prisoners—shuffling around, sometimes breathing or whimpering.

There was also an incessant dripping as water from the sea and the rain leaked down through the brickwork. Regulus took a deep breath and focused all his energy on his happiest memories:

_Getting sorted into Slytherin, his heart bursting with pride…_

_Sirius hiding him away from their grandfather, taking the beating instead…_

_Sirius hugging him close on his seventh birthday…_

_Sirius holding his hand in the hospital wing after his first quidditch game, gently kissing each finger and whispering…_

That last one did the trick. A jet of silver burst from Regulus’s wand and swirled down the corridor. In the flash of light, Regulus saw several dementors skitter away down adjacent corridors, like cockroaches fleeing the sun. He saw the awestruck eyes of several prisoners light up in brief rapture as his patronus wavered, twisted, and finally settled into its final form.

The silver dog padded its way back to Regulus obediently, and he reached out to pet it. It felt soft, almost like a real dog that had been swimming. This patronus had been much better than his original. This one was true, was _real_.

Was _Sirius._

“Take me to him,” Regulus asked his patronus. The dog looked up at him knowingly. “Take me to my brother,” Regulus urged.

Down the hall they went. Each step lighter than the last, because Regulus was _getting closer._ Most of the cells they passed were empty, and a few housed what looked like dirty piles of rags but Regulus knew to actually be prisoners long gone from reality.

Finally, at the very end after an entire row of empty cells, Regulus found his brother. There were three dementors outside his door, whether they were a permanent fixture or just there because Sirius was no longer locked in, Regulus wasn’t sure, but he told them to leave.

“Go,” he said confidently. “Wait elsewhere down the hall. I want to talk to my brother without you looming over us.”

As if to reiterate his master’s words, Regulus’s patronus stepped forward and growled threateningly.

The dementors left slowly and angrily, their cloaks billowing, low hisses escaping their decaying mouths.

Regulus curled a lip in disgust as they left.

“Reggie?” he heard his brother’s voice croak in disbelief.

Regulus walked forward. He must have looked like quite a sight, illuminated by his patronus and gracefully pulling the cell door open with his wand. He slid inside and allowed the bars to close behind him. On the other side, his patronus sat down to stand guard.

With another wave of his wand, Regulus lit the wet lamps on Sirius’s wall, bathing the room in a gentle glow and a bit of warmth.

Sirius had certainly looked better. Regulus took a moment to appreciate just how meticulously groomed his brother’s trademark “disheveled” look had always been. For all the carefree, tousled hair and tastefully ripped clothing had always seemed so casual, but now...now Sirius really did look like he’d been put through the wringer.

His normally sleek hair was not playfully frenzied but rather tangled and dirty. His clothes were ripped horribly, but not carefully and certainly not fashionably. He looked uncomfortable. There was a gauntness to his eyes and face and Regulus was amazed at how defeated his brother looked after less than one day in Azkaban.

 _One night in jail plus one horrible night at the Potters’,_ he reminded himself.

“Hello, Sirius,” Regulus said with a smile. “We certainly haven’t spoken in awhile.”

“What is this?” Sirius said hoarsely. “They said Mother and Father wanted to see me. I don’t understand why.”

Regulus shrugged. “Dad is in the lobby,” he explained. Seeing Sirius’s look of disgust, Regulus continued, “I don’t think he’ll be coming in. Mum wanted him to send me in first.”

“For what purpose?” Sirius snapped. “What kind of twisted game is this? I’ve been told Crouch superseded my trial, and that I’m not even going to get a chance to defend myself. Have you all just come here to gloat?”

“Of course not, Sirius,” Regulus said. “I know you’re innocent.”

Sirius looked at him suspiciously. It seemed that part of him was wary of Regulus's presence at all—as though it were possible that his little brother was merely a delusion brought about by the dementors.

“Mum and Dad do, too,” Regulus said matter-of-factly. “But to be honest, I don’t think they care. Sirius, I’m here to give you their offer.”

“What offer?” Sirius spat. He sounded defiant, but Regulus could hear the edges of his voice crack and he knew that Sirius would seriously consider his words if it meant getting out of this place.

Regulus took a step forward and took Sirius’s cold hand in his. He brought Sirius’s hand up to his face and smiled coyly in the flickering torchlight.

“Me,” he said simply.

“What are you talking about?” Sirius demanded. He was eyeing Regulus’s wand hungrily.

“They want to take you home, Sirius.”

Sirius snorted and took a step back from his brother. “That’s the most ridiculous thing I’ve ever heard. I’m not welcome in that place, and I wouldn’t go back if I could.”

Regulus bit his lip. “So you’d rather stay here?” he asked in a small voice.

“Don’t be stupid, I’ve no intention of staying here,” Sirius said loudly. “I’m innocent, they can’t keep me here forever.”

Regulus shook his head. “You said yourself that Crouch killed your trial. Did you think he was going to change his mind? And what would you even do if you got the chance to take the stand? I read the papers, Sirius...they’ve got a lot on you. It really looks like...”

“Well I didn’t do it!” Sirius yelled. “It was that goddam _rat_ who betrayed me, betrayed _them_. Bastard fakes his own death and gets me blamed for everything, I—”

“Siri,” Regulus said. “None of it matters.” He flittered closer to his brother. Beneath all the death and decay of the island he could still smell Sirius’s soft skin and hair, could still feel the little jolts of pleasure and fear that ran through his veins whenever their eyes met. “Mum and Dad will let you come home, and this whole nightmare can end.”

Sirius narrowed his eyes. “There’s nothing for me in that house, I might as well be stuck here...”

“There’s me,” Regulus said softly.

“Exactly,” Sirius spat. “There’s nothing.”

Regulus hung his head. “You could...you could just come home for awhile,” he said desperately. “Just lie to Mum and Dad and then leave after you’re free.”

“And have them send me back here on some trumped up charge the instant I break ranks? Fat chance,” Sirius said harshly, although there was consideration in his eyes, and Regulus knew he was thinking through the logistics of such a plan.

“I thought...maybe we could...” Regulus tapered off, biting his lip. He shouldn’t be afraid. He was armed, Sirius was wandless. Sirius was weak from prison and all Regulus had to do was yell for the dementors and he’d see Sirius thrown in solitary confinement.

So why was Sirius still so deliciously intimidating? Why did Regulus feel again like he was twelve years old, chasing desperately after Sirius in the courtyard, only to be shoved away, his classmates laughing?

“What was that?” Sirius asked.

Regulus steeled himself. “I thought maybe we could leave together?”

Sirius laughed so loudly that it startled Regulus’s patronus and the shield around them temporarily flickered. Regulus’s patronus let out a low growl and Sirius cast a nervous glance at it as he quieted down.

“What are you on about?” he asked, turning to his brother. “Don’t think that’s part of Mummy and Daddy’s little plan.”

“No, I added that bit myself,” Regulus said boldly. “I’m supposed to come here and tell you that if you come back home you can have your title and...well, me. But once you’re out, there’s no—”

“Stop,” Sirius held up a hand. He tugged Regulus to him by his sleeve. “You were serious before? When you said those two were trying to entice me home with...you?”

Regulus nodded. He started to speak but before he could manage, Sirius had struck him hard on the face, sending him spiraling into the bars of the cell. His patronus howled and leaped up.

“You little _snake_ ,” Sirius hissed, advancing on Regulus, who was trying to pick himself up off the ground. “Just what did you tell them?”

“N—nothing.”

“So this is your plan to get me back home! How do you expect me to leave their grasp if they’ve the knowledge that would land me right back in here?”

“I didn’t tell them!” Regulus screamed. His patronus was pawing at him through the bars. “I didn’t say anything, and I don’t think they know much. Mother just guessed that you were fond of me...or that you still maybe cared for me a little more than the rest of them.”

“I don’t believe you,” Sirius hissed. “We swore they’d never know. You gave me your word that you wouldn’t tell a soul, or else I never would have...”

“What?” Regulus asked, pulling himself up by the bars of his brother’s cell. “Never would have loved me?”

“Never would have done something so incredibly stupid!” Sirius spat the words with such venom that Regulus flinched. There was a burning sensation in his eyes and to his horror, he realized he was close to tears. Behind him, his patronus whined and began to dim. Sirius looked to the fading dog with horror.

“Reg,” he said carefully. He reached out to Regulus like he was trying to calm a skittish animal. “Reggie, I’m sorry, come here...”

Regulus pulled out his wand but dropped it. Sirius snatched it from the ground. At this point, Regulus’s patronus was barking like mad, throwing itself at the cell door, trying to maul Sirius through the bars. The warm radius around the patronus was shrinking and Regulus felt himself leave it as he shuffled away from Sirius’s advances. Regulus bumped into Sirius’s hard bed and fell backwards onto the cold bedding, shaking as the horrible thoughts came back.

“Regulus,” Sirius gasped. His voice sounded faraway to Regulus’s ears, and incredibly pained as Regulus’s protections continued to falter and the influence of the prison came back. “Reg, honey, I didn’t mean it like that. Come back to me, sweetheart, think of something happy. Bring your patronus back...”

Regulus let Sirius pull him up so he was at least sitting upright on the bed.

“This is why you haven’t spoken to me in so long?” Regulus asked pathetically.

“What?”

“I was a mistake? I’m...a ‘stupid’ mistake? Nothing more?” Regulus cast his eyes to the tiny window near the ceiling of Sirius’s cell. Outside it he could barely see the tip of the crescent moon, finally risen high enough in the sky to cast some additional light into the cell.

Sirius knelt in front of him, one hand on Regulus’s face, the other gently rubbing his leg. “Don’t say that, Regulus, you know that’s not what I meant.”

“What then?”

Sirius sighed. “I shouldn’t have...when we were kids, and you...”

Regulus looked down at his brother quizzically. Sirius groaned in frustration.

“You were _thirteen_ , Reg,” Sirius said in disgust. “I shouldn’t have touched you.”

“I’m not thirteen now,” Regulus said coyly. Sirius glared at him. Behind them, Regulus’s patronus began to stabilize, though it did not calm down.

“Can you call that thing off?” Sirius jerked his head towards the patronus, now shoving its fanged muzzle through the bars, snapping.

“He’s just trying to protect me.”

“From _me_?” Sirius asked gruffly.

Regulus rubbed at the bruise that was forming on his face. “Apparently,” he said sadly. “Siri, you’ve never hit me before...”

Sirius crossed his arms over Regulus’s lap and lay his head down. “I’m sorry, Reggie, it’s this place. I don’t like what it does to me...how depressed and angry I get. I can’t believe I’m to stay here forever.”

“You’re not,” Regulus said earnestly. “I told you, Mum and Dad are going to get you out, if you let them.”

Sirius looked at him with a pained expression. “What a choice,” he said. “Imprisoned here or imprisoned back home.”

“They don’t know, Siri, and I’d never tell them. I’d never tell anyone. I don’t want you in trouble for giving in to me.”

Sirius smiled. “You were always very demanding, even back then.”

Regulus smiled and wiped at his eyes, trying to compose himself. “So you’ll come home?” he asked hopefully. “You’ll let them get you out? Fake wanting to come back...for me?”

Sirius bit his lip.

Regulus had no intention of backing down without a fight. In the last twenty-four hours he’d gone from being certain he was going to die to having his safety from the Dark Lord assured, only to have that euphoria stamped down when he’d seen the news. Now that he’d been given a chance to get Sirius back, he wasn’t going to let the opportunity slip by.

“Please Sirius? You don’t even have to stay at Grimmauld Place; Mum and Dad would be happy to shack you up at a different estate...and I’m sure they’d let you take me with you.”

“Regulus...”

Regulus pulled childishly at the front of Sirius’s robes. “I don’t much care for being hit so hard in the face,” he said smoothly, working out clasps with deft fingers until Sirius’s robes fell back, exposing the dark, button-up shirt below. “But I don’t mind a few slaps elsewhere. In fact,” he smiled broadly. “I think I’d rather enjoy it.”

“Regulus, don’t you dare—”

But Regulus was emboldened. He leaned forward and brought his lips to Sirius’s, drinking him in hungrily. Through the grime and the sweat, Sirius still tasted as he always had—hot like a firecracker and sweet like stolen wine. Now it was the good memories that came flooding back, aided and abetted by Regulus’s strengthening patronus.

_Hidden away from the rest of the Black Family dinner party, in the hedges where no one could see them…_

_Lazing by the lake out back of Uncle Cygnus’s house, counting fireflies in the night sky…_

_Falling asleep on the rooftop, buried under Sirius’s shared jacket, nowhere to look but up…_

Sirius fell backwards and Regulus slid to the ground to meet him, crawling like a lynx into his lap, continuing to kiss him almost frantically.

“Regulus, god,” Sirius hissed in the brief moments he could manage to talk. “Fuck, I’m...Reg, I’m disgusting right now. You don’t want...not here!”

Regulus only chuckled. “Sirius,” he said, pawing at his brother’s shirt, desperate to feel his flesh against his own. “You painted over my eyes years ago, and there’s nothing that can steal that image from me.”

Sirius groaned and fell back completely. Flat on his back on the stone floor of the cell, he closed his eyes while Regulus continued to crawl up his body. “This is what I was talking about, you and your words, Reggie, you’re some kind of devil.”

Regulus reared back to look down at his handiwork. Sirius’s exposed chest was covered in rising red kiss marks and light scratches from Regulus’s ministrations. Regulus tugged at the waistband of Sirius’s trousers. “Haven’t you always wanted your very own fallen angel?”

Sirius moaned lightly. “It’s no good if I can’t control you,” he argued.

Regulus leaned back and slid out of his robes. He folded them neatly and set them on the driest, cleanest space he could find on Sirius’s bed. Then he felt a tug from behind as Sirius pulled him by his shirt collar.

Regulus whimpered but let Sirius lead him back to the front bars of the cell. With a smile, he leaned lazily against the bars, gripping them lightly and smiling over his shoulder at Sirius, who still looked indignant.

“I don’t know,” Regulus said, grinning. “You seem to have a pretty good handle on me.”

“Shut up,” Sirius snarled, pushing Regulus’s head down. His forehead missed colliding with the cold bars by millimeters.

Then Sirius was behind him, flush against his back and holding him trapped against the bars. Regulus shuddered despite the warmth radiating from his patronus, which was now sitting stoicly to the side, eyeing Sirius warily.

For a moment, Sirius seemed to soak in Regulus’s warmth. Regulus could feel his brother nosing at the back of his neck, peppering him with light kisses and breathing deeply.

Regulus arched back against him and Sirius actually stepped back. Regulus turned around in confusion.

“I...I don’t think I can,” Sirius explained. “Not here. Really, Reg,” he added, seeing the crushed look on his brother’s face. “It’s just that it’s so cold and dark and _miserable._ I don’t think that I... _can_.”

Regulus shook his head. “The incorrigible Sirius Black surely isn’t about to be stymied by a little _cold_?” he asked incredulously. Sirius glared at him.

“Come here,” Regulus said and Sirius returned to his side. Regulus led his patronus closer until it was inches from Sirius, separated only by the cell door. Regulus motioned for Sirius to reach out.

Sirius seemed wary about putting anything withing biting range of Regulus’s patronus, but Regulus assured him it would be okay.

“Give him a pat, he’ll warm you up.”

Finally, Sirius complied, reaching one hand out tentatively to stroke the dog’s muzzle.

“And while you do that,” Regulus said, sinking down to his knees in between the bars and Sirius’s legs. “I’ll see about what I can contribute.”

Regulus quickly unclasped his brother’s trousers and felt Sirius start. His brother didn’t stop him, though, and so Regulus set about doing what he’d thought he may never get to do again.

He freed Sirius’s cock and wasted no time taking him straight into his mouth. For all Sirius’s previous griping, he seemed to have no trouble at all. Regulus hummed contentedly as he felt Sirius come to life in his mouth. Sirius was gripping the bars above him tightly with one hand, the other gnarled in the silver fur covering his patronus’s neck.

Soon Regulus was pulling back and watching Sirius’s cock bob in front of his face at full attention. Playfully, he pawed at it until he had a grip on the base, then took just the head in his mouth, tonguing the slit and staring up at his brother with half-closed eyes.

“Fuck,” Sirius nearly cried. He released Regulus patronus and instead pulled his brother up by his collar until they were face to face again, Regulus’s back flush against the bars of the cell. “Where did you get so good? Just who have you been fucking?”

Regulus shuddered. He reveled for a moment in the delicious jealously burning in Sirius’s voice until his brother slapped him hard again, then took hold of him by the throat.

“No one,” Regulus promised, his voice raspy. “It’s just the contrast that’s making it so much better.”

“What?”

“It’s the pull of the dementors and the patronus that has you on the edge,” Regulus explained. “I can feel it, too.”

As if to explain himself, Regulus pressed his waist forward and ground his own erection against Sirius’s thigh.

Sirius still seemed unsure.

Regulus popped open the buttons on his own shirt and then moved down to his zipper. “I’m only yours, Sirius,” he assured him. “When you come home with me, you’ll see. It will be just like we always dreamed about...before.”

This time it was Sirius who went in for the kiss, swallowing Regulus’s very breath. When he slid down to work on Regulus’s neck, Regulus saw stars.

“Gods, Sirius,” Regulus squealed when his brother bit down on his shoulder. “There could never be anyone else... _fuck!”_ Sirius’s teeth grazed the hollow of his throat, his hands reached for Regulus’s cock. “You’ll see...I’ll be all yours. I’ll never leave your bedroom!”

Regulus relaxed and let Sirius maul his face and neck for awhile longer. He reveled in the attention. Sirius was strong like this, frightening almost, but Regulus wanted him desperately. There was always something chaotically frenzied about Sirius’s affections, as though he wanted more than he could take. For them, it had always seemed that no second could be wasted, for who knew when the prying eyes of their family might catch them? Sirius had always been panicked, fast and greedy.

Regulus mewled as his brother ground against him. “S—Sirius,” he whined.

Sirius slowed and looked at his brother in concern. Regulus could see the shining silver of his patronus reflected in Sirius’s grey eyes.

“No,” Sirius said firmly, knowing in an instant what Regulus was asking for. “Not a chance.”

“Please, Sirius,” Regulus begged, but Sirius stood firm.

“No, we’ve nothing here to get you ready. I’d hurt you.”

“You have my wand,” Regulus said petulantly. Sirius shook his head.

“They’ll search your wand on your way out,” he said. “You want to explain to Father why you cast a lubrication charm while you were in here?”

“Fine,” Regulus pouted. “I don’t need it.”

“Regulus, I won’t hurt you.”

Regulus led Sirius’s hand to his hair, willing him to grip it tightly and pull. “But you know that’s what I like.”

Sirius tugged Regulus’s head back harshly, bringing tears to his eyes and exposing his throat. Sirius kissed his adam’s apple lightly and relaxed his grip. “This is different, baby,” he said, brushing aside the wetness falling from Regulus’s lashes. “I could tear you up and not even realize it. And you’re far too precious to me. This is my line, and it’s killing me to draw it, so don’t ask again.”

“But, Sirius...”

“ _What did I just say?_ ” Sirius took a tight grip on his jaw. “Merlin, you really do want to be punished tonight, don’t you?”

“Why do you think I came down here?”

“You're a cheeky little brat,” Sirius hissed. He squeezed Regulus’s cock snugly against his, eliciting a breathy moan from his brother. “Did Mum and Dad even send you here at all? Or did you just sneak in to get what you wanted?”

“You overestimate me,” Regulus gasped while Sirius set up a generous pace, stroking them off together. “Do you think I could have gotten a visitation to a convicted Death Eater without the help from Mother and Father?”

“Oh, I think you could pretty easily,” Sirius said smugly. “With that talented little mouth of yours.”

“How many times must I tell you that yours is the only cock I want to taste?”

“Prove it,” Sirius snarled, stepping back suddenly. Regulus crumpled forward, finally no longer pressed harshly against the bars of the cell. He dropped obediently to his knees and took Sirius in his mouth once more.

He brushed his lips against the shaft of Sirius’s cock, breathing gently and whispering, “I really want you to come home, Sirius.”

“I will!” Sirius yelled, leaning forward and keening in frustration when Regulus moved with him, ghosting the lightest of kisses over his hot flesh. “Just...Regulus you little fucker, finish me off.”

“Make me,” Regulus said with a smirk. In an instant, Sirius had one hand knotted in his hair, the other prizing open his jaw.

“Why do you do this to me?” Sirius asked breathlessly. “I just want to be sweet to you, why do you encourage the worst in me?”

Sirius tightened his grip; Regulus could tell he was doing so to stop his fingers from shaking. Knowing his brother was close, Regulus whimpered sweetly and pulled off slowly. He heard Sirius’s breath catch as he came.

“You know I like to see it coat your face,” Sirius whined quietly as Regulus swallowed the last of his come and leaned back. He ran his tongue slowly over his swollen lips.

“And you know I prefer to taste every last drop of you,” he said smugly.

“You selfish little slut,” Sirius said, redoing his trousers.

Regulus rolled his eyes and lay back on the floor. “I thought it was a generous compromise, since you wouldn’t give me what I wanted,” he said forlornly.

Sirius growled and crouched down next to his brother, crawling up his body until they were flat against each other. “Stop pressing me, little one—”

“Don’t call me that!”

“I’ll call you what I want, and I’ll make you come how I want.”

Regulus scoffed. He opened his mouth to say something snarky only to yelp instead as Sirius slapped his bare thigh—hard.

“Sirius,” Regulus whined, but he let his brother grab ahold of him by the throat with nary a protest. Sirius used his free hand to deftly pull Regulus closer and closer to the edge, alternating between tugging mercilessly on his weeping cock and reddening his pale skin with sharp slaps.

Regulus writhed and gasped, begging Sirius not to stop. He wasn’t going to last long.

Sirius squeezed tightly on his throat and Regulus came, shuddering. Sirius cupped a gentle hand over him to catch most of his release and then slid them both down against the wall of the cell. With a contented sigh, Regulus took ahold of Sirius’s wrist and set about cleaning him off with gentle licks. Sirius watched him, shaking his head fondly.

“Come here,” Sirius said, pulling Regulus to him. He gently righted Regulus’s clothes and then tucked him carefully against his chest. Regulus buried his face against Sirius’s collarbone, letting his brother pepper him with soft touches and feather-light kisses.

“I don’t need full-on aftercare from a few light smacks, Sirius,” Regulus griped, but he made no move to stop his brother’s ministrations. Sirius ran a hand smoothly up and down Regulus’s back and fixed him with a stern stare.

“Well I do, you kinky little fuck. So stop complaining and let me do this.”

Regulus leaned back and let Sirius card his fingers through his hair, coming to a rest at the base of his neck and massaging lightly.

“You’re spoiling me.”

“It’s all you were ever good for,” Sirius responded, but he was smiling gently.

Regulus relaxed and let himself sink fully into Sirius’s arms. There was still a pleasant burning radiating up his legs and he could still feel the ghost of Sirius’s grip on his neck. Sirius was humming to him softly and that was when Regulus let his guard down.

“What’s this?” Sirius asked, concerned, and Regulus’s eyes shot open again. Sirius was pushing back the sleeve of his right arm, slowly revealing the long, brutal cut he’d placed there to pay his blood sacrifice to Lord Voldemort’s cave.

Regulus had never bothered to heal the wound. It had stopped bleeding on its own and he had figured himself for dead, anyway. He’d also been too scared to approach his parents or a healer for help, afraid he would be discovered.

“Oh, nothing,” Regulus said in what he hoped was an off-hand voice. He tried to wrest his arm from Sirius’s grip, but his brother wasn’t releasing him.

“Reggie, this looks absolutely brutal...how did this happen?”

Regulus tried frantically to turn his brain on in time. He was still so pleasantly fuzzy from his orgasm that his normally quick wit was too far out of his reach.

“I...” but it was too late. There was nothing he could say now. He had paused for too long and Sirius was narrowing his eyes in suspicion. Even the best crafted lie would be met with disbelief at this point.

“I cut myself,” Regulus answered truthfully.

“Reggie, why?”

Regulus looked down. “Please don’t make me tell you, Sirius. I can promise you it won’t happen again.”

“Regulus, you know that’s not going to work, now why don’t you want to tell me what happened?”

Regulus looked up at him with shining eyes. He had been so close...Sirius had said he was going to come home. Regulus bit his lip. “If I tell you, you’ll be so very cross. And then you won’t take me with you...you’ll leave me with Mother and Father.”

“Didn’t I just say I was going to come home with you?” Sirius asked harshly. “You can tell Father—” He jerked his head in the vague direction of the prison entrance. “—whatever you need. I’ll play nice for them.”

“You’ll hate me,” Regulus insisted.

“There’s no need for all this.” Sirius tightened his grip on his brother, as though he were nervous Regulus might try to run away. Outside the cell door, Regulus’s patronus was on high alert again, shuffling back and forth along the bars. “Regulus, just tell me.”

Regulus sighed in defeat. Perhaps it was better this way. Maybe it was best if Sirius rejected him now, before he got his hopes up too high. Regulus knew he couldn’t truly explain his exploits in the cave without starting with his enlistment, and so after a deep breath, he pulled back his other sleeve, as well. In the flickering glow of the torches and the silver shine of his patronus, the Dark Mark on his arm was clear.

It had faded somewhat since the Dark Lord’s death the previous evening, but there was no mistaking it.

“Oh, Reggie,” Sirius crooned, and Regulus released a breath he didn’t realize he’d been holding. He had honestly expected to be struck, to be flung off his brother’s lap and onto the floor. But Sirius looked as concerned as ever.

“Did He...” Sirius examined Regulus’s forearm more closely. “Did He _burn_ this into you? Why?”

“All the Dark Lord’s followers were branded,” Regulus explained softly. Part of him was terrified to speak, to confirm what up until this point had just been conjecture. “It’s how He...summoned us.”

Sirius looked deeply disturbed by this revelation. “All right,” he said. “Keep going, tell me what happened to your other arm.”

“I didn’t think you’d let me get much past this point,” Regulus admitted.

Sirius laughed sharply and Regulus jumped in his arms. “Honestly, Reggie, did you think I didn’t know?”

“You—”

Sirius sighed deeply and returned to stroking Regulus’s hair, letting his sleeve fall back to cover the Dark Mark again.

“Of course I fucking knew, _Mummy_ told me,” Sirius said and Regulus gasped. “Shortly after I moved out of James’s and into my own place, I came to see her again...asking for you, of course.” Sirius flashed him a smile that Regulus couldn’t help but return.

So Sirius hadn’t given up after one attempt. He had really come back multiple times to Grimmauld Place.

“Anyway, she didn’t really need to confirm what anyone with half a brain could have already guessed. I knew you’d been suckered into it, Reggie. Though it still hurt to hear. I think part of me was hoping I’d’ve come back for you in time...”

“Is that why you haven’t spoken to me in so many years?”

It was Sirius’s turn to look away. “Reg, I wasn’t sure what to say. And...I was scared.”

“Scared?” Regulus asked in disbelief. It seemed to him that Sirius feared nothing.

“Scared,” Sirius confirmed. “That when I saw you again I wouldn’t recognize you.”

All Regulus could think to say was, “I’m sorry.”

There was a melancholic—almost depressed—look on Sirius’s face, and Regulus could tell he was sinking into his own memories. Bringing up Regulus’s work for the Dark Lord...bringing up James...it had to hurt.

Then Sirius shook his head slightly and turned to look down at Regulus again, his smile back. “Really, Reggie,” he said, sounding like a smug parent who’s caught their child in a lie. “How exactly did you think you were going to hide this from me, anyway?” He ran his fingers up Regulus’s chest, brushing against the buttons on his shirt and coming to rest at his collar. “Sure, we’re in the middle of a prison right now, but did you really think I’d not be stripping you naked the first instant I had you alone back home?”

Regulus hung his head. He really hadn’t thought that far ahead. He’d been avoiding thoughts of his mark altogether, actually.

“I—I didn’t think...everything’s happened so fast.”

“Shh,” Sirius stroked his brother’s cheek. “You little idiot.”

Regulus looked up reproachfully.

“Well you are an idiot,” Sirius said firmly. “You were an idiot to join the Death Eaters, an idiot to try and hide it from me, and an absolute _moron_ for thinking it would change how I feel about you.”

Part of Regulus still doubted his brother’s words, despite the hope that they injected into his heart. He wanted to double check, to pry Sirius for more details, to ask if Sirius truly didn’t blame Regulus—however lightly—for the death of his friends. But he decided not to tempt fate at the moment, instead opting to bask in his brother’s affections for a few more minutes.

They could talk another time.

 _Another time…_ More time was something Regulus had not thought he’d have on this Earth, much less with his brother.

“I’m still waiting to hear why you sliced open your arm, Reg,” Sirius’s voice jarred Regulus from his reverie. “I’m assuming since you just outed yourself, that it has something to do with Voldemort?”

Regulus groaned, hiding his face in Sirius’s shirt. He could feel his own wand jabbing at him from Sirius’s front pocket.

"Mother and Father were going to threaten you if you didn't come willingly," he said, his voice muffled. 

"What?"

"If you didn't want to come home with them, they were going to threaten to turn me in to the Aurors. They said it would just be a bluff, but..."

Sirius kissed the rest of Regulus's words from his mouth. "Regulus, I'm honestly insulted that you think I'd be so cruel as to willingly allow them to throw you in here. Now stop stalling and tell me the whole truth."

“You’re going to be so mad at me...”

“Now, Regulus,” Sirius said. There was a finality to his tone that brokered no nonsense and Regulus relented.

And so he spilled his ultimate secret—the one he’d been so sure would see him killed. Sirius listened quite calmly as Regulus related his plan in its entirety: how he had discovered the Dark Lord’s secret, how he’d known he needed to destroy the locket to make the man truly mortal again.

The more Regulus spoke, a small niggling doubt began to flutter up into his mind. Since he had not actually destroyed the Horcrux yet, did that mean that the Dark Lord was not truly dead?

He did not voice this concern to Sirius just now. Instead he recounted his decision to consume the Dark Lord’s potion, and his final orders to Kreacher. Orders that the house elf had blatantly ignored.

As Regulus was just explaining where in his bedroom he’d hidden the locket, Sirius exploded.

“How fucking _dare_ you?” he screamed. Regulus was so scared that he yanked his wand from Sirius’s pocket on instinct and leaped to his feet, backing away with his wand raised.

“I—I—” Regulus sputtered.

“Was that your master plan, Regulus?” Sirius demanded. “To just waltz to your death like that? Kill yourself and leave me never knowing what happened to you?”

“I’m fine,” Regulus insisted. “Kreacher dragged me out of the water. He disobeyed my direct order and—”

“You’re god damn right he did!” Sirius’s voice was surely carrying throughout the prison block. Regulus wondered vaguely if any of the other prisoners where aware enough to understand what he was saying. “I ordered that dumb beast to keep you safe! And in case you’re forgetting, _little_ brother, disowned or not, I still outrank you.”

Sirius reached out a hand, clearly motioning for Regulus to lower his wand and return to him.

Regulus shook his head slowly. He backed up until his back was once again flush with the cell door. Sirius glared at him.

“Come back here,” he said sternly. “I’m not finished...discussing this with you.”

“Er, any chance we could discuss it later?”

“Regulus!” Sirius took a step forward and Regulus yelped. He pushed open the door and dashed to the other side, sliding it shut just before Sirius could reach him.

Regulus leaned briefly against the bars. “Next time I come see you in here, I’ll be...prepared, yeah?” Sirius reached for the door and Regulus yelped again. Unable to lock the door himself, Regulus backed up and let his patronus surge forward, snarling and leaping onto its hind legs to keep Sirius at bay. From the corner of his eye, Regulus saw a few of the dementors gliding back towards them.

Regulus gave Sirius the most innocent smile he could muster and started walking slowly backwards from his brother’s cell, his patronus receding with him as the dementors slid back into place guarding the door. He could see his brother glaring at him.

“Well...Sirius, I think I really should be getting back to Father before he comes in here looking for me. I’ll convey your message to him and I’m sure he’ll be able to get you out and home in a few weeks or so. I’ll have him bring me back for another visit in the meantime, and I promise we can discuss this situation more thoroughly, once I’ve found a way to...calm you,” Regulus added with a small wink.

“Regulus Black, when I get ahold of you...”

“I love you! I'll see you in a few days!” Regulus shouted, before he turned around and ran the length of the cell block, his patronus bounding along beside him, dissipating just as he reached the door.

* * *

“Well,” Orion said shortly. “What did you learn?”

Regulus looked up at his father. After a moment of silence, Orion sighed and pulled Regulus forward by his shirt, muttering, “honestly.” He smoothed down the front of Regulus’s collar and uncrumpled his shirt. Regulus blushed as his father gently prodded at his battered face. “I sent you in there to talk, not to brawl, Regulus really...”

Regulus sighed in relief. “My apologies, Father. Sirius wasn’t too pleased about my leaving without him.”

“Was he, now?” Orion led Regulus back to the front desk. The woman from earlier looked up immediately and without waiting for Orion to speak, rushed off to summon the charter boat. Orion watched her panicked rush with a smug smile. When they were alone, he turned back to his son.

“Did he do it?” Orion asked.

“No,” said Regulus resolutely. “I’m sure of it.”

Orion sighed. “You’re positive?” he asked.

“Yes,” Regulus snapped, a little insulted. Orion had sent him in his stead specifically because if there was anyone in the Black family who could get an honest read of Sirius, it was Regulus. And _now_ his father chose to doubt him?

“Very well,” Orion conceded. He took a deep breath and took in the empty room around them.

The dingy carpet and dim, flickering lights didn’t feel as frightening to Regulus as they had been when he and his father had first arrived. There was still a pleasant tingle in his legs and a flutter in his heart that even the encroaching presence of the dementors couldn’t suck from him.

“That certainly makes things...trickier, though not impossible. I can contact the minister tomorrow to set things in motion, if your brother is...ready?”

Regulus bit back a devilish smile before saying solemnly, “I don’t believe so, Father. He’s still pretty resistant to the idea of coming home.”

Orion raised an eyebrow.

“Said he’d rather rot in prison forever than accept any help from the likes of us.”

Orion narrowed his eyes and Regulus held his breath. His father’s eyes seemed to sear right through him, searching for any lies or disobedience.

“Very well,” Orion finally said with a gentle sigh. “We’ll give him a few weeks in here before returning. I’ve no use for a son that doesn’t... _want_ to come home.”

“Of course not, Father,” Regulus said seriously. The employee returned to wave them outside and lead them to their boat. As they stepped out into the howling winds and spritzy air, Regulus let his father lead him with that possessive, vice-like grip on his shoulder that he so favored. “Give me a few minutes with him when we come back, and I’ll _definitely_ be able to...persuade him to reclaim his title.”

Orion’s infuriating smile returned. “I’m sure you will,” he said, stepping onto the dock with Regulus following obediently. Orion raked his eyes up and down his son’s body appraisingly. “I’m sure you will.”

Regulus’s breath caught in his throat. A cruel gust of wind nearly tore his shirt from his body. “F—father?” he asked nervously.

“We’ll return on the tenth,” Orion said, his gaze turned to the sea before him. “Before the Wizengamot votes to replace those seats. That should ensure your mother and I hold the majority opinion to overturn your brother’s sentence.”

“I—”

“Quiet, Regulus,” Orion said sharply as they got into the boat. He fixed Regulus with a steady stare. He then unclasped his own cloak and draped it over his son’s shoulders and Regulus realized with horror that he had left his robes in Sirius’s cell. Orion smiled cruelly at the look of terror on Regulus’s face. “After all, talking is hardly the forte of that pretty mouth of yours.”

**Author's Note:**

> What even is this? xD Lord, what have I done?


End file.
